With regard to power semiconductor modules, there are ones in which a semiconductor chip(s) is/are fixed on a circuit board of a multi-layered substrate and a main terminal(s) and a control terminal(s) are each fixed on the circuit board at one end, with the other end penetrating through an opening provided on a resin case and extending outwardly therefrom. Such main terminals and control terminals that are not integrated with a resin case by insert molding, in other words, terminals that are provided independently of a resin case, are called “independent terminals”.
A power semiconductor module comprising independent terminals is described in Patent Document 1. FIG. 8A is a plan view of the power semiconductor module described in Patent Document 1, and FIG. 8B is a cross-sectional view of FIG. 8A taken along the line B-B. In a power semiconductor module 100 shown in FIGS. 8A and 8B, multi-layered substrates 12 are fixed on a heat-dissipating base 11 by a bonding material (not shown) such as a solder. Each multi-layered substrate 12 is constituted by a metal plate 12a, an insulating plate 12b and a circuit board 12c, which are laminated with each other. In one region of the circuit board 12c of the multi-layered substrate 12, the lower end of a main terminal 13 is bonded electrically and mechanically by a solder 22. Further, in other region of the circuit board 12c, the lower end of a control terminal 140 is bonded electrically and mechanically by the solder 22. A resin case 15 is arranged in such a manner to cover the multi-layered substrates 12 and fixed on the heat-dissipating base 11 using an adhesive (not shown).
FIG. 8C is an enlarged view showing the principal part of each main terminal 13 in the vicinity of its upper end, which is taken in the direction of C as indicated in FIG. 8B. The upper end of the main terminal 13 has an inverted U-shape formed by an upper surface portion 13a and two side surface portions 13b connected to each end of the upper surface portion. The upper end of the main terminal 13 extends outwardly through an opening 16 of the resin case 15. Between the two side surface portions 13b of the main terminal 13, a nut case 19, which is a resin body having a nut 191 embedded therein, is inserted.
FIG. 8D is an enlarged view showing the vicinity of a region D of FIG. 8B, that is, an enlarged view showing the vicinity of the upper end of each control terminal 140. The upper end of the control terminal 140 extends outwardly through an opening 17 of the resin case 15. The control terminal 140 has a first protrusion 140a and a second protrusion 140b, which are spaced from each other. Between the first protrusion 140a and the second protrusion 140b, a recess 140c is formed.
A resin block 18, which has a convex step that fits into the recess 140c of the control terminal 140, is inserted into the opening 17 of the resin case 15 for the control terminal 140. The recess 140c is engaged with a tip of the resin block 18. This allows the control terminal 140 to be precisely positioned in the horizontal direction and the movement thereof in the vertical direction caused by an external load to be inhibited.
The upper end of the control terminal 140 requires a high positional accuracy since it is connected to a connector or a printed circuit board. Particularly, the control terminal 140, which is an independent terminal, may have a lower positional accuracy than a control terminal insert-molded in the resin case 15. Therefore, it has been tried to improve the positional accuracy by engaging the control terminal 140 with the resin block 18 as shown in FIG. 8D.
However, the positioning accuracy of the upper end of the control terminal 140 may be reduced depending on the positional accuracy in bonding of the lower end of the control terminal 140 to the circuit board of the multi-layered substrate 12. In addition, from the standpoints of the tolerance of the control terminal 140 and the workability in fixation of the resin case 15, a clearance is provided between the opening 17 of the resin case 15 and the control terminal 140 passed through the opening 17. When this clearance is large, the positioning accuracy of the control terminal 140 may be deteriorated.